I have a 2000 Mitsubishi Mirage with a turbo'd 2003 4G94 engine and ECU swapped in. Everything seems to be wired up correctly with the exception of the tach... The way it was, I was getting no reading out of it whatsoever, so I went in and grounded it and ran a line to tap directly into the ECU. I started with pin 89 (crank position sensor) as it has worked for some of my fellow Miragers' cars, but that lead to the tach reading about 7500-8000 at idle, and it was pegging at throttle, though it would randomly come back around 7000-7500 and stay steady there. I tried to tap pin 58 (engine speed detector) afterward, and received no response from the tach at all. I've checked over both of my wiring diagrams, and everything points to pin 58, so I'm stumped. Any suggestions?